In an announcement earlier this year, the group said,www.camillellamas.fr/Nike-Air-Zoom-Spiridon-Femme-Homme-c-66_67.html “It is clear that some forms of technology would www.aazmotos.fr/Nike-Air-Max-270-Femme-c-28_29.html provide an athlete with assistance that runs contrary to the values of the sport.” It has since appointed a technical committee www.ranmoorpharmacy.co.uk/Nike-Air-Max-270-Womens-c-4_6.html to study the shoe question, and to make a report with recommendations. (The report was originally intended to be released to the public by the end of the year; it will www.raheembakare.co.uknow reportedly be www.camillellamas.fr/ released in 2020.)When we asked Nike last year about whether its shoes might violate I.A.A.F. rules, a spokesman said the shoe “meets all I.A.A.www.anwaltskurse.de/Nike-Air-Max-270-Damen-c-4_5.html F. product requirements and does not require any special inspection or www.philharmonia.fr/Nike-Internationalist-Femme-c-82_83.html approval.”On Thursday, the company said in a statement, “We respect the I.A.A.F. and the spirit of their rules,www.aralys.fr/Adidas-ZX-Flux-Femme-c-106_107.html and we do not create any running shoes that return more energy than the runner expends.”

There is no such thing as a large-scale randomized control trial for www.aralys.fr/Nike-Air-Max-97-Femme-c-35_36.htmlmarathons and shoes, but there is Strava,www.ranmoorpharmacy.co.uk/Nike-Air-Max-90-Womens-c-7_9.html a fitness app that calls itself the social network for athletes. Nearly each weekend, thousands of runners compete in races, www.mariavera.es/Adidas-ZX-Flux-Mujer-c-98_100.html record their performance data on satellite watches or smartphones, and upload their race data to the app. This data includes things like a race name, finish time, per-mile splits and overall www.carlosvisuara.es/Nike-Air-Max-90-Mujer-c-18_20.html elevation profile. And about one in four races includes self-reported information about a runner’s shoes.In all, this data includes race results from www.ranmoorpharmacy.co.uk/Adidas-NMD-Womens-c-28_30.html about 577,000 marathons and 496,000 half marathons in dozens www.carlosvisuara.es/Nike-Internationalist-Mujer-c-58_60.htmlof countries from April 2014 to December 2019.These approaches are essentially identical to the ones The Times used www.annieemmerson.co.uk/Nike-Internationalist-Womens-c-83_84.html last summer. See that article for more examples and methodological details.

We measured the shoes’ performance using four different methods — each with its own www.aazmotos.fr/Nike-Air-Max-95-Femme-c-36_37.htmlstrengths and flaws:None of these www.philharmonia.fr/Nike-Air-Max-90-Femme-c-28_29.html approaches are perfect, but they all point to the same conclusion: Something is happening in races with the Vaporfly and Nike Next% shoes www.raheembakare.co.uk/Nike-Air-Max-90-Womens-c-25_27.html that is not happening with most any other kind of popular shoe.More than 110,000 athletes uploaded data for more than one marathon, and about 47,000 uploaded data for three or more www.anjakemper.de/Adidas-Superstar-Damen-c-7_8.html marathons. The Strava data allows us to follow these repeat racers over time and as they change shoes.